Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/66—Polyesters containing oxygen in the form of ether groups
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4326—Condensation or reaction polymers
  • D04H1/435—Polyesters
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/542—Adhesive fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
  • D04H1/74—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being orientated, e.g. in parallel (anisotropic fleeces)
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
  • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/507—Polyesters

Definitions

• This invention concerns improvements in and relating to synthetic fibers and especially to polyester fibers that are not used in the traditional textile sense, i.e. that are not used as yarns for making traditional textiles by weaving or knitting, but as water-dispersible fibers for making wet-laid materials, including nonwoven fabrics, and board and paper-making, and sometimes referred to therefore as papermaker staple, or in pulps for other purposes, such as often referred to as fluff pulp for use, e.g. in incontinence products and for other absorbent purposes, and for other non-traditional textile uses.
• Synthetic fibers such as polyester fibers, and textile yarns thereof have been known and used commercially for several decades, having been first suggested by W. H. Carothers, U.S. Patent No. 2,071,251 and then by Whinfield and Dickson, U.S. Patent No. 2,465,319.
• the synthetic polyester polymer that has been used most for fibers for commercial purposes is poly(ethylene terephthalate), made from ethylene glycol and dimethyl terephthalate or terephthalic acid, and its fibers have been used for apparel and other purposes.
• water-dispersible synthetic fiber and especially polyester fiber.
• Such water-dispersible fiber is used in various non-woven applications, including paper-making, including board-making, and wet-laid non-woven fabrics, sometimes as part of a blend, often with large amounts of wood pulp, e.g. for paper-making, and/or with other synthetic fibers, but also in applications requiring only polyester fiber, i.e. unblended with other fiber.
• the term "fiber” is used broadly herein, so as to include, in particular, such finely-divided water-dispersible filamentary materials as are sometimes referred to as fibrids or fibrils, e.g. in some of the above art, such as Yoshida.
• Continuous filaments are not themselves water-dispersible.
• synthetic fibers are generally first formed from synthetic polymers by extrusion (melt-spinning in the case of polyesters) to form continuous filaments that may be comminuted when the actual water-dispersible fibers are required; so continuous filaments coated with the appropriate water-dispersing coating are generally precursors, i.e. intermediates between the polymer mass and the eventual cut fiber that is water-dispersible.
• water-dispersible polyester fiber is of poly(ethylene terephthalate), and the filaments are initially prepared in essentially the same general way as conventional polyester fiber for textile staple, except that, previously, most water-dispersible polyester fiber has not been crimped, whereas any polyester staple fiber for use in textile yarns is generally crimped, the crimping being performed on filaments, while in the form of tow, before conversion into staple fiber, because good crimp properties in the staple fiber provide the desired frictional properties desirable for downstream processing and in the resultant spun yarns.
• water-dispersible polyester fiber has generally been prepared by melt-spinning the polyester into filaments, combining the filaments to form a tow, drawing, applying a suitable water-dispersing coating to impart water-dispersible properties, generally in the same way as a finish is applied to a tow of conventional textile filaments, and then (generally without any crimping or with imparting only some mild wavy undulations in some cases so that the final sheet made therefrom has extra bulk and a three-dimensional matrix), the two has been cut to the desired cut length, i.e. to form the cut fibers that are water-dispersible.
• Such cut fiber has generally been sold in the form of bales of fiber compressed together.
• Polyester (and other synthetic) fibers are naturally hydrophobic, significantly more so than cellulose wood pulps or cotton. This hydrophobic nature has posed a problem in regard to their suitability for wet-laying processes, as disclosed by Ring et al. in U.S. Patent No. 4,007,083, Hawkins in U.S. Patent Nos. 4,137,181, 4,179,543 and 4,294,883, and Viscose Canal in British Patent No. 958,430. As disclosed therein, it has been difficult to find a way to overcome the inherent hydrophobic character of the polyester fiber without creating foam or causing the fibers to flocculate.
• polyester fiberfill in relation to the field of slickened polyester fiberfill (an entirely separate technical field), some of us (in Du Pont) have improved polyester fiberfill so that it is slickened with a coating of a new copolyester having polyether segments as well polyester linkages, and wherein such copolyester contains residues of a chemical compound containing polar groups such as hydroxy groups (OH) and quaternary ammonium groups and amine groups (referred to generically as NH) and are filing thereon a copending application simultaneously herewith (DP-4349-A), the contents of which are hereby incorporated by reference.
• Preferred polyesters, among such new copolyesters are the subject of copending PCT/US 89/00829, filed March 6, 1989, entitled “Modified Hydrophilic Polyesters", the contents of which are hereby incorporated by reference.
• improved water-dispersible synthetic polymer fibers especially polyester fibers, that are coated with a coating of a copolyester having polyether segments as well as polyester linkages, and wherein the improvement is characterized in that the copolyester contains residues of a chemical compound containing polar groups such as hydroxyl groups (OH) and quaternary ammonium and amine groups (referred to generically as NH).
• a chemical compound containing polar groups such as hydroxyl groups (OH) and quaternary ammonium and amine groups (referred to generically as NH).
• Preferred such chemical compounds are polyhydroxy compounds containing at least 3 carbon atoms with hydroxyl functional groups. Sorbitol is an example of a polyhydroxy compound that has given very good results, and is available at a reasonable cost.
• new fibers coated with these new modified copolyesters are conveniently modified further by cross-­linking with a suitable cross-linking agent and that, by such like means, further bonding of the coating in situ is achieved to improve the durability of the coating on the original fiber substrate.
• This improved durability is believed very important, in practice, for several reasons, e.g. to prevent leaching during wet deposition if effective water-dispersibility is to be achieved using the equipment and processes currently available for commercial manufacture, and, especially for incontinence and other absorbent purposes in fluff pulp, improved liquid transport along the coated fibers is believed very helpful and important.
• Suitable cross-linking action may be by direct esterification, with agents that include polycarboxylic acids, such as citric acid, transesterification, with esters, e.g., of citric acid with lower alcohols, for instance containing up to 6 carbon atoms, or by other cross-­linking-type reactions, as described in the copending applications.
• agents that include polycarboxylic acids such as citric acid, transesterification, with esters, e.g., of citric acid with lower alcohols, for instance containing up to 6 carbon atoms, or by other cross-­linking-type reactions, as described in the copending applications.
• an improved process for preparing water-dispersible synthetic polymer fiber, especially polyester fiber, in the form of cut fibers, and their precursor continuous filaments comprising the steps of extruding the polymer (e.g. melt-spinning polyester) into filaments, processing a bundle of filaments in the form of a tow, if desired by drawing and possibly annealing to increase orientation and crystallinity, if desired crimping to produce crimped filaments, and relaxing the crimped filaments, and converting the filaments into staple fibers, wherein the fibers in the form of filaments or staple fibers are coated with a water-dispersing coating, and wherein such coating is a copolyester having polyether segments as well as polyester linkages, characterized in that the fibers are coated with a copolyester containing residues of a chemical compound containing polar groups as aforesaid, such as hydroxyl groups (OH) and (NH) groups (quaternary ammoni
• copolyesters may prove appropriate for commercial applications, as indicated in copending DP-4349-A and PCT/US 89/00829, referred to hereinabove, with preferred base copolyesters (i.e., before modification according to the invention) having approximately equimolar amounts of poly(oxyethylene) terephthalate and ethylene terephthalate moieties, although the amounts and specific materials may be varied to suit the desired objective.
• the polyether segment may vary upwards, e.g., up to about 85% by weight of such copolyester, such as in the range of (about) 50-85% by weight, and the ethylene terephthalate ester moieties may comprise much less, and as little as about 10% by weight, and in the range of (about) 10-35% by weight, constituting what may be regarded as a polyester linkage component, in contrast to the polyether chain component that provides hydrophilicity and other desired attributes to the coated fiber.
• water-dispersible fibers according to the present invention, it is particularly important to recognize that, by modifications that may appear to vary only slightly from each other, it is possible to get entirely different products that are especially suited for completely separate end-uses, such as paper or board, and fluff pulp for incontinence purposes.
• the amounts used will, likewise, depend on the objectives desired and the materials used, and may comprise, e.g., as much as about 20% by weight, e.g., of a (residue of a) polyhydroxy compound containing at least 3 carbon atoms with hydroxyl functional groups.
• the amounts of the copolyester coating on the fiber will vary according to desired objectives, and are expected to be relatively small, conventionally being up to about 1% by weight of the fiber, as disclosed in the copending applications referred to.
• cross-linking-type reactions and operative polyfunctional compounds to effect these are indicated in some more detail therein, and amounts will vary and depend on specific objectives (e.g., intended end-uses) and may be as much as about 10% or 12% by weight of the copolyester, e.g., in the range of about 0.5% to about 20% by weight.
• polar groups which are compatible with, and form chemical bonds with wood pulp. These bonds may be made permanent to avoid leaching as previously described by cross-linking with a variety of chemicals, themselves having sufficient free groups available to both bond the polyether segments around and onto the fiber substrate, and also to chemically bond or form looser hydrogen bonds with wood pulp in the eventual sheet structures.
• the looser bonds are usually preferred when it is desirable to permit recycling of paper products, depending on the objective.
• cross-linking agents may in themselves also have specific and possibly unusual benefits, e.g. some such sold as TYZOR, for example, can, depending on the type chosen, be activated in acid or alkaline papermaking systems to give improved opacity as well as strength improvements in that they can also bond to fillers (e.g. clay, calcium carbonate, talc, etc.) as mentioned in EP A1 0261820, referred to above.
• TYZOR e.g. some such sold as TYZOR
• fillers e.g. clay, calcium carbonate, talc, etc.
• Preferred polyester substrate fibers will normally be in the range from 0.5-20 den., however coarser deniers may be desirable for speciality paper end-uses.
• the fiber cross-section can be round, or as described in references such as are mentioned above, and may be treated by Corona, UV, laser, stretch-breaking, shrinkage or other chemical, etc... treatments and/or modifications to affect the surface as desired.
• the improvement is water-dispersibility enhances the bonding capability of the coated fibes, as indicated.
• Other advantages are shown hereinafter, but include the ability to permit lower chemical bonding temperatures to be used, and thereby to obtain improved sheet softness, and better drape, particularly in wet-laid nonwoven structures.
• the ability to incorporate other groups provides scope to impart a wide range of properties, such as bacteriostatic properties and control of odors, as mentioned in the copending applications.
• Table 1 compares measurements on sheets of open board structure, arranged to give 75-80 g/sq m (in fact being of 70-80 g/sq m, and with values normalized to compensate for small variations in weight between the various samples) prepared at 3m/min on a Bruderhaus laboratory inclined wire machine, using 550 g CTMP pulp added to 100 L water and pulped for 15 minutes, before adding any polyester fibers, then adding 16.5 g polyester fibers (except for the control) and pulping for a further 2 minutes to get good dispersion and distribution of the polyester fibers. This Furnish was then transferred to the machine chest, so that it could be diluted for forwarding to the headbox, i.e. 566 g solids in 500L - stock consistency.
• the control used 100% CTMP pulp (without polyester fibers), as a basis for comparison.
• polyester fiber In addition to the provision of improved polyester fiber, referred to herein and in the copending applications, special reference should be made to Examples 22-25 of copending application DP-4349-A (such as are incorporated herein), demonstrating the coating of fibers other than polyester, and specifically polypropylene and aramid fibers, as such improvements may be of great benefit to their use in wet-laying processes. Similar improvement can be demonstrated on acrylic, and polyamide or other synthetic fibers.
• fluff pulp such as is used for absorbence, e.g., for incontinence products.
• fluff pulp such as is used for absorbence, e.g., for incontinence products.
• attempts to provide integrity, i.e. web or pad integrity, to such products by incorporating various synthetic fibers has met with little or no practical success, unless recourse is made to thermal bonding fibers.
• Superabsorbent materials could also be improved by incorporating (economically-viable) synthetic fibers to prevent gel-block and to give improved comfort to users as regards wet incontinence products.
• coated fibers according to the present invention may be processed into a speciality improved fluff pulp, along with wood pulp, and the hydrophilic nature is improved sufficiently and permanent enough to withstand fluff-pulp processing, and multiple wetting by the ultimate consumer, with improved product performance over prior attempts.
• These fibers may be of 6 mm or longer, in length, and 0.5 denier to 20 denier, with or without crimp, in round or irregular cross-sections having an increased surface area, as indicated above.
• Pulp products both bleached and unbleached, with very low degrees of refining, 21° SR, and unrefined fluff pulp, approx. 15° SR, have been prepared on paper pilot machines or on Bruderhaus laboratory inclined wire machines to demonstrate that these coated synthetic fibers can be uniformly dispersed in percentages of up to 60% synthetic fiber using 12 mm cut lenght and 80 to 90% in 6mm cut lengths when using 1-6 denier fibers.
• the preferred levels of synthetic fiber addition to the fluff pulp remain low (2-10%) on economic grounds.
• Unexpected benefits that have been observed include rapid dewatering, and that the moisture off the wet end of the machine can be reduced by 5-20%, enabling more rapid drying, and that less suction on the wire (to help the drainage of water from the stock furnish leaving the headbox) is required.
• the improvement in through­put is very significant in practice.
• the hydrophilic coating can be firmly bonded to the new fiber
• the waster produced in diaper or other incontinence and wet wipe products
• the waster can be recycled without causing damage to the hammermill, or sticking in the system, or being inadequately re-opened into nit-free fluff.

Landscapes

• Textile Engineering (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Polyesters Or Polycarbonates (AREA)
• Paper (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Absorbent Articles And Supports Therefor (AREA)
• Nonwoven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=10633646

Family Applications (3)

Family Applications Before (1)

Family Applications After (1)

Country Status (17)

Cited By (3)

Families Citing this family (16)

Citations (5)

Family Cites Families (16)

• 1988
  • 1988-03-18 GB GB888806419A patent/GB8806419D0/en active Pending
• 1989
  • 1989-03-06 EP EP89903587A patent/EP0419489A1/de not_active Withdrawn
  • 1989-03-06 US US07/571,571 patent/US5239019A/en not_active Expired - Lifetime
  • 1989-03-06 AU AU32176/89A patent/AU3217689A/en not_active Abandoned
  • 1989-03-06 WO PCT/US1989/000829 patent/WO1989008673A2/en not_active Application Discontinuation
  • 1989-03-15 CA CA000593843A patent/CA1319456C/en not_active Expired - Fee Related
  • 1989-03-17 KR KR1019890702148A patent/KR900700686A/ko not_active Application Discontinuation
  • 1989-03-17 JP JP1503919A patent/JPH02503581A/ja active Pending
  • 1989-03-17 EP EP89302695A patent/EP0333515A3/de not_active Withdrawn
  • 1989-03-17 JP JP89503918A patent/JPH02503580A/ja active Pending
  • 1989-03-17 GR GR890100169A patent/GR890100169A/el unknown
  • 1989-03-17 ES ES8900982A patent/ES2014056A6/es not_active Expired - Lifetime
  • 1989-03-17 WO PCT/US1989/001233 patent/WO1989008736A2/en active Application Filing
  • 1989-03-17 WO PCT/US1989/001234 patent/WO1989008737A1/en active Application Filing
  • 1989-03-17 AU AU33597/89A patent/AU601106B2/en not_active Ceased
  • 1989-03-17 NZ NZ228373A patent/NZ228373A/xx unknown
  • 1989-03-17 EP EP89302698A patent/EP0336595A1/de not_active Ceased
  • 1989-03-17 KR KR1019890702147A patent/KR900700685A/ko not_active Application Discontinuation
  • 1989-03-17 NZ NZ228372A patent/NZ228372A/en unknown
  • 1989-03-18 CN CN89101586A patent/CN1036608A/zh active Pending
  • 1989-03-18 CN CN89102678A patent/CN1039855A/zh active Pending
  • 1989-03-18 CN CN89102597A patent/CN1036781A/zh active Pending
  • 1989-03-20 TR TR24889A patent/TR23905A/xx unknown
  • 1989-03-20 TR TR89/0249A patent/TR23718A/xx unknown
  • 1989-03-20 PT PT90051A patent/PT90051B/pt not_active IP Right Cessation
  • 1989-03-20 ZA ZA892100A patent/ZA892100B/xx unknown
  • 1989-03-20 ZA ZA892098A patent/ZA892098B/xx unknown
  • 1989-03-20 PT PT90052A patent/PT90052B/pt not_active IP Right Cessation
  • 1989-03-20 PT PT90053A patent/PT90053B/pt not_active IP Right Cessation
  • 1989-03-20 ZA ZA892099A patent/ZA892099B/xx unknown
  • 1989-06-28 DK DK321589A patent/DK321589A/da not_active Application Discontinuation
  • 1989-06-28 DK DK321689A patent/DK321689A/da not_active Application Discontinuation
  • 1989-06-29 FI FI893190A patent/FI893190A0/fi not_active Application Discontinuation
  • 1989-06-29 FI FI893191A patent/FI893191A/fi not_active Application Discontinuation
  • 1989-11-17 KR KR1019890702143A patent/KR900700524A/ko not_active Application Discontinuation
• 1990
  • 1990-09-17 DK DK223390A patent/DK223390A/da not_active Application Discontinuation
  • 1990-09-17 FI FI904561A patent/FI904561A0/fi not_active IP Right Cessation

Patent Citations (5)

Also Published As

Similar Documents

Legal Events